The major change will be in the way mining operations get done. The fees might just boom a lot because miners will have only one way of getting paid and that is mining fees. Because bitcoins will be mined fully and thus there will be no block that will be remained to add into the blockchain. However, whiner a transaction will be done then there will be need of miners who will just algorithmically solve the transaction and add the blocks.

On investors perspective, the demand will be very much high as whole bitcoins will be in circulation. The supply will be fulfilled already and only one thing will surge and that is demand thus rising the prices high.